Following the PR update many webmasters have noticed a drop in their PR scores this week. Some have found the value of their page rank drop to zero but traffic was not hampered.
Adam Lasnik of Google will have a look into the matter. He commented at a WebmasterWorld Forums thread that “ If you've seen your PR adjusted to a non-zero number OR you've lost significant traffic, this thread does not really apply to you.
If, however, your PR has dropped to zero AND you've not seen any significant loss in traffic from Google, rest assured that this is most likely a PR-reporting (PR on Toolbar) error; while admittedly alarming at first site, it's nothing to worry about.”